Hi dear,

            There is no other exam to get seat in any government Architecture college except JEE Mains Paper 2.Though you have qualified JEE Mains Paper 2 but you can not get seat in any of the government Architecture college offering BE. Arch. as your rank is very very less in JEE mains Paper 2.  You should try for Some good private colleges. 

Try referring Career 360 App to check reviews of colleges and their rankings. Use various Comapre tools too to compare different colleges.

All the best